Hydraulic balance for centrifugal pumps.



w. n. CARTER.

'i HYDRAULIC BALANCE FOR' CENTBIFUGAL PUMPS.` APPLICATION FILED nic. l2.me.

Patented .May 2s, 1918.

` v 2 SHEETS-SHEU'L ifm . A ATTORNEYS.

W. D. CARTER.

HYDRAULIC BALANCE FOR CENTRIFUGAL PUMPS.

APPLICATION FILED DEC.I2, |916.

Patented May 28,1918.

2 SHEETS-SHEET 2.

m Egal.,

Illini!!! ATTQRNEYS.

v hydraulic balancing device being so consrn'rs WILLIAM D. CARTER, 0FSAN' JOSE, CALIFORNIA.-

HYDRAULIC BALANCE FOR CENTRIFUGAL PUMPS.

Application led December 12, 1916. Serial No. 136,464.

This invention relates to a hydraulic bal# ance for centrifugal pumps,and pertains particularly to improvementsin pumps of the typeillustrated in my co-pendmg appllcation iled on or aboutfMay 29th, 1916,Ser. No. 100,712. u f Y 011e of the objects of the present invention isto ,provide a simple, substantial,

cheaply manufactured multi-impeller pump,

and particularly a hydraulic balancing device which will relieve theimpeller from what is vcommonly called end thrust, said structed andarranged that it will be equally eicient Whether the impellers areoperating in series or in parallel, or in multiple series, or as adouble-suction, impeller, single-stage pump or as .a multi-stage pump.-Another object of the invention is to provide an automatic,l hydraulicbalancing device which is particularly applicable where a doubleYimpeller is used and which acts with comparatively equal. eficiencywhether an' odd or even number of double impellers is employed. Furtherobjects will hereinafter appear.

The invention consists of the parts and thev construction andcombination of parts as hereinafter more fully described and claimed,having referenceto the accompanying drawings, 1n which Figure 1 is avertical crossv sectioniof a double service centrifugal pump, taken online 1 1 of Fig. 2, showing the cylindrical casing in position forcombinin the volumes received from the two si es of the double impeller,with the result commonly obtained with' the ordinary type ofdoublesuction impeller pump; this view also giving the location of thehydraulic balancing ports.

Fig. 2 is a plan view, in section, taken on l Specification of LettersPatent. atellted May 2S, 191g,

line 2 2 of Fig. l, said view being partly broken away to show the portsin the main. base casing.

Fig. 3 is a cross section on line 3 3 of Fig. 4;; the cylindrical casingbeing shown revolved on its seat in the main base casing to a positionrequired for combining the independent discharges of the two sides ofthe vdouble impeller in series, thus obtaining vthe result commonlysecured with an ordinary type of two-stage pump.

Fig. 4L 1s a plan view, 1n section, taken on line 4 4 of Fig. 3, withpart of the cylinder casing broken away toA exposeports in the mainAbase casing through which water passes when the two sides of theimpeller are connectedin series.

Fig. 5 is a Vplanview, in section, of the base casing, taken on line 4 4of Fig. 3;

Fig. 6 is an enlarged cross section of the double impeller.

Fig. 7 is a side elevation of same.

Fig. 8 is a side elevation of the cylinder casing, showing the positionof the several intake and discharging ports.

Referring to the drawings in detail, A

indicates a Abase casing in which are formed I two main passages, suchas indicated at 2 and 8. The passage 2 connects, at one end, witha'niain suction elbow 4f, and at the` opposite end with a port 5. Thepassage 3 connects at one end with a port 6 and at the (opposite endwith a port 7.

Formed at one side of the base casing is a main discharge port 8, andformin an impression in thel interior of the caslng is a passage 9, thepurpose of which will'hereinafter be described. Turnably mounted andsupported in the base casing is a cylindrical casing B which mayhereinafter be termed the volute Formed Yinsaid casing are two. volutepassages l0 `and 11 which are arranged side by side. These volutepassages are symmetrically disposed with respect to a plane half-waybetween them and are, furthermore, perpendicularto a main-driving shaft12 which extends through the base casing and the volute. Suitablysecured upon the shaft interiorly of the volute casing is a f doubleimpeller, such as indicated at y13.

'ruis impune is provided with two aimed suction openings 14 and 15 andtwo separate annular discharging passages 17 and 18 11 are a pair ofports-20 and 21, and formed in alinement with said ports is a third port22 which vcommunicates through a passage 23 with the suction side of thedischarge passagelS` formed in the impeller. Formed iu the opposite endof the base 'easing is a central opening which communicates withV vthesuction side of the discharge passage 17.

On eachside of the 'impeller are formedk concentric inner and outerannular flanges 14a-14h, tox cooperate with corresponding cylindricalsurfaces 14C-14d, inner flange 14El surrounding the' intake port 14 or15, ,and forming a running joint with the annular flange 14c in the maincasing,`the outer anges 14b forming running joints with cor` respondingcylindrical surfaces 14don the 'volute Casin flanges 14a-14?D 'on oneside of the impel er form with the adjacent side of the volute casing acounted-balancing chamber 27 While the other part of ianges 14%--14b onthe opposite side of the im the port 26 will be as follows: With Waterpeller forni a counter-balancing chamber 25 with the adjacent side ofthe base casing,- all as will be later described."

The pump constructed as here shown and' provided with a double impellermay either operate in parallel as a double-suction, single-stage pump,or in series as a tivo or niulti-stagepump. This isacconiplishcd byturning the volute casing B `Within the base casing to bring the ports2G, 21 and 22 into register or out of register with certain ports,hereinafter to be described, Which are formed in'thebase casing.`

ofthe impeller, where'itenters through the.'

1f itis desired to operate the pump as a double-suction, single-stageunit, it is accomplished kby turning the volute casing Vuntil the ports20 and 21 register With the main dischargeport 8, as shown in Figs. 1and 2. The port 22 Will then be in register with the assage 2 and itWilhtheiefore, be possible or the Water entering the suction elbow 4 totake the following path: Part of the water will enterthe intake 14 anddischarge through the annular discharge of the iin'- peller 17 into thevolute passage 10 and from said passage through port 20 into thedischargeport 8. Similarly, it is possible for Water to pass `from thesuction elbow, through the passage2, to the oppositeside intake 15 andpasses out through the annular dischargepassage 18 in thevolute 11, fromWhere it discharges through port 21 into the discharge port 8. |vvoseparate yoluraes haring the samel pressure are in ,sie

thisV manner combined and discharged impeller single-stage pump.

The foregoing construction corresponds closely to that described in myaforesaid copending case embodying essentially a pump casing having adouble impeller With two completely independent stream passagesseparated by a transverse partition, manifold passages having portsarranged so that by rotating the casing to selected positions theimpeller passages are connected in series,

'in arallel or multiple series.`

he hydraulic balancing of the impeller, when 'so operated, Will be asfollows: Formed in the volute casing, exteriorly of the volute passages10 and 11, is a'passage 24. One end of this passage communicates withthe y, volute passage 11, While the opposite end communicates with thechamber 25 formed' on one sideof the impeller. Formed in the volutecasing, on the side opposite to the chamber 25, is a port 26, one end ofWhich communicates 1with passage v 23, While the .opposite endcommunicates with the chamber 27, similar to chamber 25.

The balancing action of the passage 24 and entering the suction elbow 4it may be assuined that the pressure in the intake openings 14 and 15 ofthe impeller will be zero and that the pressure in the volute passages10 andll will be forty pounds. This pressure will, therefore, heestablished in chainruns in close proximity to the outer fiat edge orface of the inner iiange 14c and closes port 26, thereby shutting ofileakage into passage 23; While pressure in chamber 25 Would bediminished by the full effect of unrestricted leakage around the innerlflange 14a to the Suction 'elbow 4. Should this pressure become greaterthan the pressure in chamber 25, it can readily` be seen that theimpeller Will move in a direction oppositeto arrovv a. Port 28 will,therefore, become uncovered and the 'Water contained under greaterpressure in chamber 27l would dis-` charge into the passage 23 which'contains zero pressure. A perfectbalance is in this manner obtainedWithout resorting to any complicated mechanism or any :thrust bear-1,267,512 l y y i ings ormechanism whiclrwould require care andattention.

If the pump is to be operated in series as a two-stage pump, it isaccomplished by turning the volute casing until it assumes the positionshown inFigs.- 3 and. 4. Port 2O will here register with the port 6,port 21 with thewde'pression 9, and port 22 with port 7. The waterentering the suction elbow 4 would, therefore, take the following seriescircuit: It would first enter the intake 14 and the volute 10fromswhereY it would discharge through ports l'20 and 6- into thepassage 3, which, as before described, communicates with port 7 It willthen pass through port 7 and ort 22 into the passage 23, which connectswith the intake side 15 of the impeller. The water will then passthrough the annular discharge 18 of the impeller and enter the volutepassage 11 and would nally discharge through port 21 into the depression9 which communicates with the discharge port 8.

The operation 'of the hydraulic balance will in this instance be asfollows: Assuming the pressure in the suction elbow to be zero, and thepressure in the volute 10 to be forty pounds, the pressure at the intakeside 15 of the impeller would also be forty pounds as the water is herereceived from the volute 10. The water, after its passage through n`this 'side of the impeller, will discharge into the volute 11 and willhere have an additional pressure which, 4according to theory,- should beapproximately eighty pounds. The port 26' and the passage 24 are,however, so arranged that they may the pressure in the several passagesis equal or otherwise. A

This will be more readily understood from the following: If the pressureon the intake sure will cause the impeller vpounds as-it is suppliedside 14 of the impeller is zero and the pre'sthen the pressure in theintake side 15 of the-impeller will be forty pounds and the pressure inthe volute 11 will be eiglhty pounds. .The pressure in chamber 25 a sowill be eighty with water through the volute 11 andthe the passage 24from 27 will also be eighty pressure in chamber pounds as it age fromthe volute 11 around the annular running ange 14". The pressure at eachend of the runner is, therefore, practically speaking, equal, and inbuilding up, the presto'move to or away from the port 26, 'in thismanner relieving or building up pressure as conditions require.Thehydrauhc balancing arrangement employed is equally eicient whether inseries orin parallel the pump is operated or in multiple serles.

There is nothing vcompdic'ated,about this operate whether is suppliedwith water by leakr pump. t has one double impeller, each side of whichdischarges into the base through a separate volute passage in the volutecasing.

The base casing contains two sets of water passages, only .one of which'is in use at a time. TheyI are of large cross-sectional area and serveto connect the independent streams from the two sides of the impellereither in series or parallel, according to the angular position of he.volute in the base casing. That is, one position of the volute casingwill throw the combined volume of both sides .of the impeller against asingle pressure, while another position will discharge the single volumeof one side of the impeller through the other side, thereby giving twicethe pressure. The construction' 1s such that the ing.

For variable service each half of the impeller is designed to give-aswide a range of variation in head as is possible with a welldesignedsingle impeller pump, and itis evident that the combination of the twosides will give a continuous, uniform range of efficient serviceapproximately'y twice that of any other single impeller pump now on. themarket.

It is not necessary to disturb either the suction dr dischargeconnection in order to inspect the interior of this pump. Both sides ofthe impeller can be reached without removing it from the `ump body', or,if desired, the runner and s aft may be removed entirely by looseningtheset-screw in the shaft coupling, not here shown.

Having thus described my invention,what I claim and desire to secure byLetters Patent is- 1. ln a centrifugal or similar pumphaving two or moredouble service impellers each capable of series or parallel operation, apair of suction passages and a discharge passage connected with eachimpeller, means for changing the4 connection of said passages sc'thatisaid impellers may be operated in series, in parallelor in multipleseries, and

having two independent stream passages separated by a transversepartition, meansby which said passages operate in series, or in arallel,counter-balancing means for the impeller whereby the impeller isautomatically counter-balanced irrespective of whether the pump operatesin series or parallel. f 3. In a centrifugal pump, the combination of acasing, an impeller therein having two independent stream passagesseparated yse by a transverse partition, a pair or concen tric anges oneach side of the impeller,

. correspcndin anges on the casing coperating with the anges on theimpeller to form, a hydraulic 'counter-balancing chamber on.

which said chamber is immediately adjacent, v

and means by which the discharge at highest pressure is connected withthe counter-balancing' chamber et lovvest pressure.

5, The combination in a centrifugal pump haviru7 a double tion' impelleroperating in series, or" means for hydraulically balancing the two sidesthereof..

6. The combination in a centrifugal pump having a double impelleroperating in eeries, and automatic hydraulic counter-balancing chambersen the tivo sides of said inipeller with means for connecting the sideo1? high pressure or the pump with the counterbalancing chamber on thelovv presnire side ci the pump.

f?. ln a centrifugal pump, a double ilovv impeller, a casing inclosingsaid impeller, and a hydraulic balancing chamber, :termed in the casingeach end or the impeller.

8, ln a centrifugal pump, a double ovv impeller, a casing inclosing saidimpeller, a hydraulic balancing chamber Aformed in the casing at eachend of the impeller, means :for admitting Water under pressure to saidchambers, and means for automatically maintaining a balancing pressurein said chambers,-

9. ln a centrifugal pump, an impeller havlng a pair of opposed int-alieopenings and a pair ot spaced independent annular discharge passages, acasing inclosinlg the impellensaid cas' having a pair or passages formedtherein into which the impeller discharges, a balancin chamber formed inthe casing at each en of the impeller, means vfor admitting Water underressure from oneV volute passager to one balancing chamber, and aconnection formed between the opposite balancing chamber and' one of theintake passages of the impeller.

l0. lnfa centrifugal pump, an irnpeller having a pair ot opposed intakeopenings and a pair ci spaced independent annular discharge passages, acasing inclcsing the inea-aia impeller, said casing having a pair ofpassages ormed therein into which the impeller discharges, a balancingchamber formed in the casing at each end of the impeller, means foradmitting Water under pressure from one volute passageto one balancingchamber, a connection formed between the opposite balancing chamber andone of the intake passages of the impeller, and means for automaticallycutting ed said connection.

ll. ln a centrifugal pump, an impeller having a pair oli opposed intakeopenings and a pair ci spaced independent annular discharge passages, acasing inclosing-the' impeller, said casing having a painof volutepassages :formed therein into which the impeller discharges, a balancingchamber formed in the casing at each end ci the impeller, means foradmitting vvater under pressure :troni one volute passage to onebalancing chamber, and a connection formed between the oppositebalancing chamber and one of the intake passages of the impeller, saidconnection being adapted to be opened and closed by endvvise movement orthe impeller.

i2. ln a centrifugal pump, the combination of a casing and a doubleimpeller therein having tvvo independent stream passages separated by atransverse partition, means by which said passages operate in series,and connterbalancing means for automatically balancing said impelleragainst end-thrust.

i3. in a centrifugal pump, the combination orn a casing, an odd numberof double iinpellers 'therein assembled upon one driving shaft, each cisaid impellers having two independent stream passages separated by atransverse partition, means by vvhichfsaid passages operate in series,and hydraulic counterbalancing means ier automatically balancing saidimpellers against end-thrust.

la. ln a centrifugal pump, the combinaf tion et a casing, an impellertherein having vtvvo independent stream passages separated lill.

by a transverse partition, a pair of concentric iianges on the lowpressure side ci said impeller, and a large han e on the hlgh pressureside of said impe ler, corresponding Hanges on the casing coperatingwith the Hanges on the irnpeler to form a hydraulic counterbalancingchamber on each side oi the impeller, each of said counterbalancingchambers being in leakage connection with the intake, and also inleakage connection with a respective discharge column of said streampassages, and connections between the chamber ci lovver pressure withthey discharge. column of higher pressure. when the `pump is operatingin series l5. rHnacombination in a centrirugal pump, ci? doubleimpellers operating in lil@ ias

seriesLa counterbalancing chamber at each slde of each impeller, eachcounterbalancmg chamber being in leakage connection with haust passageby endwise movement-'of said Y 1o impellers.

16; The combination in a i centrifugal pump having an odd number ofdouble impellers operating' in series, and means for hydraulicallybalancing the end-thrust of said impellers.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

WILLIAM D. CARTER. Witnesses e DE LANGEY LEWIS,

J. L. WA/LLACE.

